1. Technical Field
The invention relates generally to an improved semi trailer and trailer coupling system. More particularly, the invention relates to an improved fifth wheel coupling for land use trailers. Specifically, the invention relates to a half round trailer with a fifth wheel coupling formed integral to the trailer to lower the center of gravity and increase trailer stability.
2. Background Information
The trucking industry continues to suffer from substantial increases in overhead due to fuel prices and other expenses. High costs and competition require that all aspects of the truck and trailer be optimized to minimize expenses and utilize all potential productivity. Thus, the industry is constantly in search of improvements that can increase efficiency of the trucks or the trailers in order to reduce operating costs.
The fifth wheel coupling of a tractor-trailer is a key component in the trucking industry as it is the main connection between the truck and the trailer. The fifth wheel receiver is usually mounted above the rear wheels of the truck and is arranged to receive a coupling pin. The coupling pin is located at the front of the trailer and generally extends downward from the bottom side. In operation, the fifth wheel includes an opening at the rear to allow the coupling pin to slide in, where it is then locked in place. This arrangement allows the front end of the trailer to pivot along the horizontal plane with the back of the truck to improve turning and trailer mobility.
The traditional fifth wheel coupling pin is mounted to the exterior of the trailer at the front end and extends downward from the bottom. The pin is secured within a mounting assembly that can withstand the force of the trailer weight when it is fully loaded. Normally, this means that the coupling pin is far below the bottom of the trailer and accordingly increases the overall height of the trailer during operation because it is inserted into the same fifth wheel. The increased height leads to additional wind resistance at the trailer and instability due to the higher center of gravity, both of which decrease fuel efficiency and safety.
The need thus exists for a trailer which has a lower center of gravity and can resist the drag of wind resistance. Additionally, the need exists for a fifth wheel coupling which can be mounted partially within a trailer to reduce the overall height of the front end of the trailer.